جستجوی مقالات مرتبط با کلیدواژه « natural biochar » در نشریات گروه « آب و خاک »

Soil and plant contamination with heavy elements due to industrial activities has adversely affected human health and has received much attention in recent decades. Heavy metals can endanger soil, plant and human health by entering the soil cycle and food products. In order to reduce the harmful effects of heavy metals on the soil ecosystem and food pollution, a factorial experiment was conducted in three replications in a completely randomized design in a greenhouse. The aim of this study was to investigate the effect of different amounts of natural biochar and poultry manure on the fertility of zinc and cadmium elements in a contaminated soil.

In order to conduct this research, first different levels of poultry manure (zero, 0.5, 1, 2, 4 and 8% by weight) and natural biochar (zero, 2, 4, 6, 8 and 10% Weight) were added separately to a contaminated soil. Then, 4 levels of incubation were applied to the moisture capacity of the farm (1, 2, 3 and 4 months). At the intervals mentioned from the pots, sub-samples were prepared and transferred to the laboratory. After drying in the oven at a temperature of 50-55 ºC was taken pH, EC, the total and absorbable amount of zinc and cadmium elements in them.

Comparison of mean effects of incubation and poultry manure and biochar levels showed that with increasing consumption level and incubation, soil pH decreased by 3.9% and 1.4%, respectively, and EC amount by 36.5 and 10.4 percent increased. There was a statistically significant difference between the control treatment of the control or the zero level of poultry manure and biochar with the treatment of 8% of poultry manure and biochar (statistically 5% probability level). With increasing incubation and levels of poultry manure and natural biochar, the adsorbent concentration of zinc and soil cadmium decreased significantly (P <0.05), which decreased in treatments containing poultry manure for zinc and cadmium, respectively, 19.9 and 29.5 percent, and in treatments containing natural biochar, zinc and cadmium were measured as 28.4 percent and 22.7 percent, respectively. In poultry manure treatments, the lowest zinc and cadmium concentrations extracted with DTPA extract in the fourth month and the consumption level of 8% were 304.7 and 10.9 mg/kg, respectively, and the highest amount was observed in the first month. Witness treatment (zero percent level) was observed to be 380.2 and 20.0 mg/kg, respectively. In treatments containing natural biochar, the lowest amount of zinc and cadmium extracted with DTPA extract in the fourth month and 10% consumption level were 272.4 and 12.9 mg / kg, respectively, and the highest amount was treated in the first month. The control (zero percent level) was observed to be 380.3 and 20.7 mg/kg, respectively.

According to the results of this study, the use of biochar and manure fertilizer caused a decrease in the concentration of absorbable heavy metals studied in the soil. Although treatments containing biochar and manure reduced the adsorption concentration of metals in the soil, the concentration of adsorbent metals in the soil decreased further with increasing levels of poultry manure and biochar and the incubation of the soil. In general, it can be stated that the application of poultry manure and natural biochar in the soil is an effective method to reduce the toxicity and absorbable concentration of heavy metals in the soil and also increase the yield and quality of agricultural products.

Water repellency is one of the important physical properties of soil that affects the soil moisture curve, hydraulic conductivity, and so on. The aim of present study is to investigate the effects of adding natural and artificial biochars on water repellency and some other physical and chemical properties of soil. This study was conducted in factorial design with various levels of additives (natural and waste compost biochars) in a randomized complete block design in three repetitions. The considered factors are natural biochar in four levels (0, 1, 3 and 5%) and municipal waste compost biochar in four levels (0, 1, 3 and 5%) with the total of 16 treatments. The water repellency of natural and municipal waste compost biochar was measured by means of the water drop penetration time (WDPT) test and the actual time required for infiltration ( ) was recorded for each 16 treatments. The results showed that increasing the percentage of applied biochars increased . The highest amount of  belongs to treatments No. 5 and 16 were 156 and 170 s, respectively, which increased by 98 and 99 times in comparison with the control treatment. 12 of 16 treatments were classified as wet table or non-water-repellent soil, one treatment in slightly and three treatment as strongly water repellent soil. In general, it can be said that application of biochars, especially the natural biochar, in terms of water repellency does not cause any infiltration problem. Also, it can be concluded that bulk density had an average decrease rate of 4.3% and organic matter and pH had an average increase of 2.2 and 1.8 percentage respectively.

Water is the most important limiting factor for plant growth in dry and desert regions.  Addition of soil amendments is one of the most important practices to reduce water shortage by improving soil physical properties and water use efficiency. In this study, the effect of natural and urban waste-compost biochars on the soil physical properties (e.g., bulk density, particle density, field capacity, permanent wilting point, available water, saturated hydraulic conductivity, and irrigation interval) as the most effective parameters on irrigation were investigated.  This experiment was conducted as factorial and in a completely randomized blocks design with three factors and three replications in greenhouse condition. The proposed factors were consisted of four levels of natural biochar (0, 1, 3, and 5 % of weight) and four levels of municipal waste-compost biochar (0, 1, 3, and 5 %) and a plant factor at one level (Calligonum species). The results showed that the addition of biochars to the soil had a significant increasing effect on the field capacity, available water, and irrigation intervals and a significant decreasing effect on the saturated hydraulic conductivity, bulk and particle density. Field capacity, permanent wilting point, available water and irrigation interval had an average incremental rate of 17.2, 16.8, 17.4, and 3.2% respectively and hydraulic conductivity, bulk and actual density had an average decremental rate of 39.4, 4.4 and 11.7 % respectively as compared to the control treatment. Treatment No. 13 (soil+5% natural biochar+5% urban waste compost biochar) had the most effectiveness on the above mentioned parameters.